Gaucher disease is an inherited disorder characterized by the accumulation in tissues of glucosylceramide-laden macrophages (`Gaucher cells`) as the result of a deficiency in the lysosomal enzyme glucocerebrosidase [1]. The presence of Gaucher cells is responsible for the common symptoms in Gaucher patients, such as hepatomegaly, splenomegaly, and skeletal deterioration [1].
The clinical manifestations in glucocerebrosidase-deficient individuals are very heterogeneous. Onset of clinical symptoms may occur at very young age, but the disorder may also remain virtually asymptomatic. Accurate prediction of disease severity and progression is not possible on the basis of the mutant glucocerebrosidase genotype of Gaucher patients.
During our search for sensitive markers for the presence of Gaucher cells, we discovered that in plasma of symptomatic patients chitotriosidase activity is markedly elevated [2]. Our present experience with more than 700 symptomatic Gaucher patients indicates that the average plasma chitotriosidase activity is about 1000-fold higher than the normal mean.
The discovery that activated storage macrophages are the source of the excessive plasma chitotriosidase in Gaucher patients, made us conceive that several disease conditions in which activated neutrophils and/or macrophages are involved might show detectable chitotriosidase abnormalities that can be exploited for diagnosis as well as for monitoring and optimalisation of therapeutic intervention. The feasibility and validity of this is illustrated by a number of examples, involving Gaucher disease, atherosclerosis, sarcoidosis, multiple sclerosis, arthritis and Crohn disease.
Copending U.S. patent application Ser. No. 08/486,839 describes our discovery that man contains a chitinase, named chitotriosidase, that fulfills a role in resistance against infections with chitin-containing pathogens by virtue of its ability to degrade chitin, an essential structural component of their coatings. Said patent application claims the use of chitotriosidase in therapy or prophylaxis against infectious diseases.